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毕业设计

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dq024全数字化双闭环可逆直流PWM调速系统的研究,毕业设计

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四象限变流器 PWM双闭环控制系统的计算机仿真 摘 要 :介绍了使用 SABER对四象限变流器 PWM双闭环控制系统进行计算机仿真的一套方 法 ,阐述了 PWM双闭环控制原理 ,将部分仿真波形与实际试验波形进行了对比 ,表明仿真结果是可 信的。 关键词 :四象限变流器 ;脉宽调制 ;控制系统 ;计算机仿真 ComputersimulationofPWMdoubleclosed-loop controlsystemfor4-qconverter LIBo (RollingStockResearchInstitute,ChinaAcademyofRailwaySciences,Beijing100081,China) Abstract:AcomputersimulationmethodusingSABERforPWMdoubleclosed-loopcontrolsystemfor4-qconverteris introduced.TheprincipleofPWMdoubleclosed-loopisdescribed.Comparisonofsomesimulationwaveformswithmeasuredtest waveformsshowsthesimulationresultsarebelievable. Keywords:4-qconverter;PWM;controlsystem;computersimulation 1 引言 自从 70年代产生四象限变流这种独特的交直变换拓扑结构以来 ,四象限变流器便作为交流传动电力机车交直交传动系统的电网侧变流器 ,扮演着重要角色。简言之 ,通过四象限变流器的控制 ,对电网侧 ,可以使电网电流波形接近于正弦 ,电网功率因数接近于 1,最大程度地提高电网的经济效益 ,减少电网对周围环境的电磁污染 ;对直流侧 ,在电网电压或负载发生变化 时 ,能够维持直流中间电压的稳定 ,给电机侧逆变器提供良好的工作条件。而且 ,四象限变流器可以实现牵引与再生工况间快速平滑地转换。 80 年代以来 ,随着计算机的飞速发展 ,计算机仿真技术 已逐步深入到科研、产品开发等各个领域。在电力电子领域 ,通过使用计算机仿真技术 ,设计者在设计阶段就能全面考察系统的动静态特性 ,选择合理的系统结构及参数 ,在最大程度上避免设计的盲目性 ,提高试验的一次成功率 ,缩短研制周期、节约研制成本。这种利用计算机仿真技术进行辅助设计的方法已成为电力电子研究领域的发展方向。本文介绍了使用SABER软件对四象限变流器 PWM双闭环控制系统进行计算机仿真的过程 ,并给出了仿真波形及相对照的部分实际试验波形。 2. SABER简介 SABER是美国 ANALOGY公司开发的一种可用于电力电 子、自动控制、光电、电磁、机械、液压、热工等领域的计算机仿真软件。从结构上看 ,它主要由 3部 分 组 成 :SABERSKETCH 、 SABERGUIDE 和 SABERSCOPE 。SABERSKETCH用于以图形方式输入被仿真的系统 ;SABERGUIDE把输入的系统当作一个网络 ,首先通过网络列表 (Netlist)提取系统的结构信息 ,然后通过直流分析 (DCAnalysis)得到系统的静态工作点 ,在此基础上再对系统进行时域(TimeDomain)及频域 (FrequencyDomain)范围内的各种分析 ;当对系统完成分析计算后 ,便可用 SABERSCOPE观看所有变量的波形 ,并对波形进行各种分析运算。 SABER的优点可概述如下 : nts(1)SABER秉承了模块化、自顶向下、层次化 (Hierarchy)的设计思想 ,增强了设计的科学性 ,提高了设计效率。 (2)SABER具有丰富的模型 ,它的模型库中包括了电力电子、机械、液压等领域的各种常用模型。同时 ,SABER 还给用户提供了一个硬件级的建模语言MAST。使用 MAST语言 ,可以方便地构造出自己的模型。 (3)SABER提供了强大的系统分析功能。设计者可以从各个方面对系统进行考察。在 时域方面有直流分析 (DCAnalysis)、瞬态分析 (TransientAnalysis)等 ;在频域方面有傅立叶分析 (FFT)、频响分析 (Small-SignalFrequencyAnalysis)、畸变分析 (Small-SignalDistortionAnalysis)等。 SABER 还可用于应力分析(StressAnalysis)及统计学方面的蒙特卡罗分析 (MonteCarloAnalysis)。 SABER还有一个非常实用的分析功能 参数敏感性分析 (Parametric SensitivityAnalysis),利用这种分析功能 ,设计者可以控制一个或几个参数在一定的范围内变化 ,观察它们对系统特性的影响 ,从而找出它们最合适的数值来。 (4)SABER 不仅对数模混合系统仿真得心应手 ,而且可以对由电力电子、电磁、机械、液压等数个不同系统构成的一个混合系统进行仿真。这种强大的混合仿真能力其实是 SABER的最大优点。 3. 四象限变流器 PWM双闭环控制原理 四象限变流器 PWM 双闭环控制系统的工作原理及各种参数的计算方法在文献 1和 2中已做了详尽论述 ,在此仅对四象限变流器 PWM 双闭环控制原理做一简述。 四象限变 流器作为交直交传动系统中的电网侧变流器 ,其实质是交流电网与直流中间回路进行能量交换的中间介质。当负载增加时 ,它从电网吸取更多的能量供给直流侧 ;当负载减小时 ,它将直流侧多余的能量返送给电网 ;当由牵引转入再生时 ,它使直流侧由从电网吸收能量变为向电网输送能量 ,反之亦然。在对能量的这些控制过程中 ,四象限变流器通过 PWM 双闭环控制算法来实现维持直流中间电压稳定 ,使电网功率因数接近于 1,电网电流波形接近于正弦等控制特性。 由四象限变流器的瞬时功率平衡公式 uNiN=UdId可以看出 ,四象限变流器对能量的控制实际体现在对 iN 的控制上 ,对 Ud 和功率因数的控制最终都是通过控制 iN来实现。 在控制过程中只要保持矢量 UL 与 UN 的正交 ,就可保证电网的基波功率因数等于 1。四象限变流器 PWM双闭环控制正是基于此原理实现的。以 Ud 给定值与反馈值之差作为电压调节器的输入 ,以 U 给定值与反馈值之差作为相位调节器的输入 ,2 个调节器的输出经 PWM 调制对矢量 U S1 进行控制 ,达到稳定 Ud 和保证 U=0的目的 ,从而实现电压、相位双闭环控制。 4.计算机仿真 4.1 仿真系统构成 整个仿真系统由主电路及控制电路构成。主电路根据图 1来构建。交流侧使用理想交 流电压源 ,因为进行的是系统级仿真 ,所以对 GTO 元件做了合理简化 ,将其近似为理想开关。主电路中的电阻、电感、电容器、理想开关、交流电压源等均采用 SABER提供的模型。 四象限变流器 PWM 双闭环控制系统的计算机仿真图 4 仿真系统结构图控制电路构建 ,包括滤波器、整形、相位检测、软启动控制器、相位调节器、电压调节器、 PWM控制器、直流中间电压动态过压限制器等模块。除滤波器采用 SABER提供的模型外 ,其余模块均使用 MAST 语言自己建立。这个仿真系统充分利用了ntsSABER的数模混合仿真功能 ,达到了将四象限变流器主电路与控 制电路结合起来进行仿真的目的 负载的急剧突变有可能使四象限变流器不能及时将直流侧能量返送给交流侧 ,从而使直流中间电压快速上升 ,造成过压 ,对系统产生严重损害。因此 ,应在直流侧加入一个保护环节 直流中间电压动态过压限制器。当直流中间电压快速上升 ,四象限变流器来不及将其调回给定值时 ,直流中间电压动态过压限制器工作 ,通过斩波限压的方式 ,将直流中间电压限制在保护值以下 ,协助四象限变流器将直流中间电压调回到给定值上。 4.2 仿真策略 主电路参数 :uN=1200V,给定值 Ud为 2600V,系统额定输出功率为 1200kW。 在仿真过程中 ,用在直流侧投切电阻的方法来模拟负载的突变。负载分 3 次投入 ,每投入 1个电阻 ,系统输出功率升高 400kW,第 3个电阻投入后 ,系统输出功率升为 1200kW。然后 ,将 3 个电阻一起切除 ,与此同时 ,将一个串直流电压源、电阻和电感的支路投入 ,模拟由满功率牵引突然转为满功率再生的情况。通过这些操作 ,可以观察直流中间电压 Ud和电网电流 iN的动态响应 ,衡量控制系统的动态调节性能。 4.3 仿真结果 当直流中间环节出现过压时 ,直流中间电压动态过压限制器将会进行限压 ,比较了有和没有直流中间电压动态过压限制器时直 流中间电压的波形。从中可以看出 ,通过限制器的动作 ,过电压的波峰被削掉了 ,直流中间电压被限制在保护值以下。 5. 结论 通过 SABER的仿真 ,证明了四象限变流器 PWM双闭环控制系统具有良好的控制性能 ,可以满足大功率交流传动电力机车对四象限变流器控制的要求。通过对四象限变流器 PWM双闭环控制系统的仿真 ,也说明了 SABER的确是一个优秀的仿真软件 ,是电力电子设计者得力的 CAD工具。在国家“九五”重点攻关课题“ 200kmh动力分散交流传动电动车组牵引变流器及其控制系统的研制”中 ,应充分利用计算机仿真这一先进的设计手 段 ,以提高设计质量。 参考文献 : 1邵公寅 ,李中浩 .四象限变流器系统 J.铁道学报 ,1983,(3). 2陈鸿荫 ,张 黎 .四象限变流器两相两重供电的数字控制系统 J. 铁道学报 ,1983,(9). 3ShenJTaufiqJA.Computeraideddesignofthecontrolsystemofa3-level highpowerPWMconverterforrailwaytractionapplicationC.ANALOGY POWERELECTRONICSSEMINAR,1996. 4李 军 ,桂武鸣 .用 Saber作交直交系统仿真 J.机车电传动 , 1997,(4). 5李 军 .一个四象限变流器系统的计算机仿真 J.机车电传动 , 1996,(6). nts1. Preface Since the 70s produced four quadrants to change to flow this kind of to hand over to keep the transformation to rush toward the structure specially, four quadrants change to flow the machine and then be the exchanges spreads to move the electric power motorcycle to hand over to keep hand over to spread the charged barbed wire net side of move the system to change to flow the machine, the impersonation emphasizes the important person color.Chien speech, pass the control that four quadrants change to flow the machine, to the charged barbed wire net side, can make a form of the charged barbed wire net electric current near to in the sine, the charged barbed wire net power factor near to in 1, an economic performance that raises the charged barbed wire net, reduce the electromagnetism pollution of charged barbed wire net to the surroundings environment; to the direct current side, in the charged barbed wire net electric voltage or the load occurrence varieties Hour, can maintain the direct current in the center the stability of the electric voltage, go against to change the machine to provide the good work condition to the electrical engineering side.And, four quadrants change to flow the machine and can carry out to lead to convert with the reborn work condition quickly and smoothly.Since 80s, fly along with the calculator to develop soon, the calculator imitate the true technique to have already gone deep into each realms, such as research and the product development.etc. gradually.At the electric power electronics realm, pass to use the calculator to imitate the true technique, design is designing the stage ability the overall investigation system moves the static state characteristic, choice reasonable of system structure and parameter, avoid the blindness of design on the biggest degree, a success rate that exaltation experiment, shorten to research to manufacture the period and economize to research to manufacture the cost.This kind of makes use of the calculator to imitate the true technique to carry on the method that lends support to the design to have become the development direction that the electric power electronics studies the realm.This text introduces the usage SABER software to change to flow the machine PWM double to shut the wreath control system to carry on the calculator to imitate the true process to four quadrants, and give imitate a form and opposite the part that shine on is actual to experiment a form. 2. Brief introduction of SABER SABER is the American ANALOGY company develops a kind of and can used for electric power electronics, automatic control, the light electricity, electromagnetism, machine, liquids press, hot work etc. realm of calculator imitate the true software.See from the structure, it mainly is constitute by 3 parts: SABERSKETCH, SABERGUIDE and SABERSCOPE.The SABERSKETCH used for is imitate with the sketch method importation true system; the SABERGUIDE chases the importation of in the light of network of system, pass the structure information that the network row form( Netlist) withdraws the system first, then order through the static state work that the direct current analysis( DCAnalysis) gets the system, within the scope of this foundation up carry on to the system again area( TimeDomain) and area of ( FrequencyDomain) various analysis; be to complete the analytical calculation to the system after, can take a look at all forms that change the quantity with the SABERSCOPE then, and carry on various analysis ntsoperation to a form. The SABER advantage can say all as follows: (1)The SABER takes orders the mold piece to turn, from the crest get down, the layer turn( Hierarchy) of design thought, strengthenned science of design, raise the design efficiency. (2)The SABER has abundant model, including the electric power electronics, machine, liquid to press various in common use model of the realm of etc. in its model database.At the same time, the SABER returns to provide a hardware class for customer to set up the mold language MAST.Use the language of MAST, can construct the model of an oneself expediently. (3)The SABER provided the strong system analysis function.Design can carry on the investigation to the system from the each aspect.At the area contain direct current analysis( DCAnalysis), in a sudden the analysis( TransientAnalysis) etc.; have the to sign the leafs analysis( FFT), to ring the analysis( Small- SignalFrequencyAnalysis), the mutation analysis( Small- SignalDistortionAnalysis).etc. in the area of .The SABER can also used for should the dint analysis( StressAnalysis) and covariances learn the aspect to receive especially the card Luos analysis( MonteCarloAnalysis).The SABER still has a very practical analytical function- parameter sensitivity analysis( Parametric SensitivityAnalysis), the one who make use of this kind of analysis function, design can control an or a few parameterses within the scope of certain variety, observe the influence of them upon the system characteristic, thus find out their quite the cheese number. (4)SABER not only the logarithms mold admixture system really imitate with proficiency, and can to really be pressed a hybrid system that several different systems of etc. constitute by the electric power electronics, electromagnetism, machine, liquid to carry on imitate.This kind of strong admixture imitates biggest advantage that the true ability is a SABER in fact. 3. Four quadrants change to flow the machine PWM double to shut the wreath control principle Four quadrants change to flow the machine PWM double calculation method of the work principle and various parameter that shuts the wreath control system to have already done the detailed treatise in cultural heritage1 and2, changing to flow the machine PWM double to shut the wreath control principle to do a Chien to say to four quadrants only here. Four quadrants change to flow the machine conduct and actions to hand over to keep hand over to spread to move the charged barbed wire net in the system side to change to flow the machine, in fact quality is the exchanges charged barbed wire net and direct currents in the center the back track carries on the energy commutation of middle lie the quality.When the load increase, it absorbs more energies to supply the direct current side from the charged barbed wire net; be When the load let up, it turn the direct current side the surplus of the energy return to give the charged barbed wire net; be from lead into the rebirth the hour, it make the direct current side from absorb the energy to change into toward charged barbed wire net to transport the energy from the charged barbed wire net, vice versa.In to energy of these control process, four quadrants change to flow the machine to shut the wreath control calculate way through a PWM double to carry out to ntsmaintain the direct current in the center electric voltage stability, make the charged barbed wire net power factor near to in 1, a form of the charged barbed wire net electric current is near to in sine etc. control characteristic. Change the equilibrium formula uNiN of moment power of flow the machine from four quadrants= the UdId can see, four quadrants change to flow the machine to the actual body of the control of the energy now to iN control up, to Ud and the control of the power factors end is all to pass to control the iN to carry out. In control process as long as keep the vector U L and U the N is hand over, can guarantee that a power of factor of the charged barbed wire net be equal to 1.Four quadrants change to flow the machine PWM double to shut the wreath control exactly according to this principle realization of.With the Ud give settle value and feedback the bad value is the importation of the electric voltage modulator, with the U give settle value and feedback value of bad conduct and actions mutually the importation of a modulator,2 exportations of modulator was make by PWM to the vector U the S1 carries on the control, attain stable Ud and guarantee the U=0 of purpose, thus carry out the electric voltage, mutually a double shuts the wreath control. 4.The calculator really imitate 4.1 Imitate the true system constitute Whole imitate the true system to be constitute by the main electric circuit and the control electric circuit.Main electric circuit according to figure 1 to set up.Communicate the side usage ideal exchanges electric voltage source, what to carry on really is a system class to imitate, so did the reasonable simplification to the component of GTO, looking like it as the ideal switch.The electric resistance, the electricity feeling, capacitor, ideal switch, the exchanges electric voltage source.etc. within main electric circuit all adopt the model that SABER provide. Four quadrants change to flow the machine PWM double calculator that shuts the wreath control system to imitate the true figure 4 imitate the true system structure diagram control electric circuit to set up, include the filter, orthopedics, mutually an examination, soft start controller, mutually a modulator, electric voltage modulator, controller of PWM, direct current in the center the electric voltage dynamic state leads to press to limit the machine etc. mold piece.In addition to filter adopting the model that SABER provide, the rest mold piece all uses the MAST language oneselfs establishment.This few mold admixture that imitated the true system to make use of the SABER well imitates the true function, coming to a to change four quadrants to flow the machine main electric circuit and the control electric circuit knots to put together to carry on imitating the true purpose The nasty play mutation of the load probably make four quadrants change flow the machine cant return the direct current side energy to give the exchanges side in time, thus making direct current in the center fast rising of electric voltage, resulted in press, produce the serious damage to the system.Therefore, should join a protection link- direct current in the direct current side in the center the electric voltage dynamic state lead press the restrict machine.When direct current in the center fast rising of electric voltage, four quadrants change to flow the machine to adjust it back too late to settle the value, direct current in the center the electric voltage dynamic state leads to press to limit the machine work, passing the way that cut a limits press, protect direct current in the center electric ntsvoltage limit at value as follows, help four quadrants to change to flow the machine to adjust direct current in the center electric voltage to return to to settle value up. 4.2 Imitate the true strategy Main electric circuit parameter: uN=1200 Vs, give settle to be worth the Ud as 2600 Vs, the system sum settles to output the power as 1200 kWs. In imitate true process, use the mutation that the method that slices the electric resistance in the direct current side hurl imitates the load.The load divides to throw in 3 times, throwing in 1 electric resistance each time, the system outputs the power to go up the 400 kWs, the 3 electric resistance devotion after, system output the power advances to the 1200 kWs.Then, be lead by the full power 3 electric resistances cut off together, at the same time, pay a direct current electric voltage source, electric resistance and the electricity feelings the road devotion, imitate suddenly to turn into the full power rebirth of circumstance.Pass these operations, can observe the direct current in the center the electric voltage Ud and th